Polarized Emissivity and Kirchhoff’s Law
An expression for the polarized emissivity of a material is obtained with the Stokes vector–Mueller matrixpolarization formalism. The result obtained is that thermally emitted radiance might have a circularpolarization component. In addition, the emissivity depends only on the reflectance matrix.
Resnick, Andrew; Persons, Chris; and Lindquist, George, "Polarized Emissivity and Kirchhoff’s Law" (1999). Physics Faculty Publications. 327.